Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, so the description does not need to repeat those. It adds useful context by specifying the output is exactly the current label plus confidence and nothing else, which aligns with and complements the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single short sentence that immediately conveys the tool's purpose and output scope. Every word earns its place, and the constraint 'only' is front-loaded into the key information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter read-only tool with no output schema, the description adequately tells the agent what to expect: the current regime label and confidence only. It could be more complete by defining possible label values or confidence scale, but the simplicity of the tool and the strong annotations make this sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool has zero parameters and the input schema is empty, so there is no parameter semantics burden for the description to carry. The baseline of 4 applies because there are no parameters requiring explanation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly identifies the tool as returning the current SPX dealer regime label and confidence, with 'only' emphasizing its narrow scope. It does not use a verb phrase, but the resource and output are unmistakable and it is effectively distinguished from the sibling get_regime_segments by saying it returns only the label and confidence.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The word 'Current' and 'only' imply this tool is for a point-in-time label and confidence, not for historical or detailed segment data. However, it never explicitly names alternatives like get_regime_segments or states when-not-to-use this tool, leaving some guidance implied rather than explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.